From: Jim Peters (jim_at_uazu.net)
Date: 2001-12-05 20:07:42
Doug Sutherland wrote:
> (lots of stuff)
On licencing:
I've had a quick search on this on the 'net. Try "open-source
hardware design" in Google. There are several open-source
microprocessor cores and so on available. See:
http://www.free-ip.com/
http://www.mdronline.com/mpr_public/editorials/edit15_03.html
However, Richard Stallman (originator of the GNU GPL) has written
something on this subject. Basically he says that a copyright on a
circuit layout isn't much use, as anyone can legally copy the circuit
itself, generate their own layout and effectively re-use your work
without restriction (assuming no patents are in force):
http://features.linuxtoday.com/news_story.php3?ltsn=1999-06-22-005-05-NW-LF
So, in this case, I would say, make the circuit design freely
available, and stick the firmware source under the GPL. You could
also stick the circuit layout files (the EAGLE files, which count as
source code) under the GPL, which would encourage people to contribute
fixes and improvements to the circuit layout back to the project.
Fortunately, this part (licencing) doesn't seem to be as complicated
as it might have been, as far as I can make out.
On what hardware to go with:
My preference would be for a decent sampling rate (200Hz+), a good
range (I'm interested in <1Hz signals), and a good solid and reliable
design. I don't know how many channels I'd need because I've never
done EEG.
If, as Doug suggests, assembly isn't likely to be cheap for small
numbers, does that mean the project would be aiming for home-
constructors initially, selling only the PCB, letting them get all the
parts from their local suppliers ? Or if the parts aren't readily
available, selling kits of PCB+components ?
There are companies that specialize in kits like this. If this is an
open and well-tested design, they might be interested in doing all
this work for us. If their kits would turn out to be too expensive,
people can just get the parts themselves anyway.
Are there perhaps safety regulations on this kind of device, though --
otherwise surely EEG monitors would be available as kits already ? Is
this the reason why the project seems to be aiming for manufacturing a
pre-assembled unit ?
If the target is home-constructors, how hard would it be to have a PCB
that could be adapted for different uses by the constructor
him/herself, e.g. serial-out versus IrDA, 9V cell versus
Nicad+charger, according to his/her needs ?
Doug Sutherland wrote:
> You definitely need FFT source,
There are very good open-source FFT libraries available. Most of this
kind of signal processing stuff is already out there, somewhere.
(Especially in UNIX-land).
I personally live at the command-line, so almost all the code I'll
write will be command-line driven. Probably, for end users, you'd be
wanting simplified GUI apps. This isn't my scene. However, any work
that I or others do with the low-level apps will make the work of a
GUI app coder much much easier.
Currently I can cross-compile audio command-line tools for Windows and
Linux using MinGW. It might be possible to make software that
compiles on both Linux and Windows using one of the libraries that is
designed for writing portable games, such as SDL (Simple Directmedia
Layer).
Jim
-- Jim Peters (_)/=\~/_(_) Uazú (_) /=\ ~/_ (_) jim@ (_) /=\ ~/_ (_) www. uazu.net (_) ____ /=\ ____ ~/_ ____ (_) uazu.net
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